The invention relates to a tufting gripper for tufting machines for the manufacture of tufted goods, in particular for the manufacture of tufted goods with cut pile.
In tufting machines, tufting grippers are disposed to grip thread loops that have previously been formed by tufting needles, said needles punching a pile thread through a planar backing material. In order to produce cut pile, a large number of tufting grippers held on a sinker interact with cutting knives that are also held on a sinker and that carry out a cutting motion opposing the movement of the tufting grippers. In order to reduce wear on the cutting edge of the tufting gripper, said gripper frequently comprises an insert that is provided with the cutting edge. Such a tufting gripper has been known from EP 1 953 290. The gripper has a cutting insert consisting of a hard metal, said insert being placed in a pocket of the gripper body and being secured in said pocked by projections on the pocket edge. These projections have been produced by plastic deformation of the pocket edge. This arrangement, and this type of fastening of the insert, offers great advantages, in particular in instances in which the tufting gripper must exhibit a certain lateral flexibility and the hard-metal insert exhibits great stiffness. On the other hand, a certain gap must exist between the pocket edge and the hard-metal insert.
Some pile threads used for the manufacture of loop pile, but in particular for the manufacture of cut pile, comprise very fine filaments that slide freely along the lower edge of the tufting gripper and are also not supposed to become caught in gaps or steps between the insert and the gripper body. Even if such gaps are filled by hard solder, remaining steps can result in damage to the thread, which has to be prevented in order to achieve good product quality.
Considering this, it is the object of the invention to disclose a concept that permits the formation of high-quality pile, even in the case of pile threads that are difficult to process.